<!DOCTYPE html>
<html>
<head>
<style>
.democlass {
  color: red;
}
</style>
</head>
<body>
<h1 class="democlass">Hello World</h1>
<p>Click the button to display the value of the class attribute node of the h1 element.</p>
<button onclick="myFunction()">Try it</button>
<p id="demo"></p>
<script>
function myFunction() {
  var elmnt = document.getElementsByTagName("H1")[0];
  var attr = elmnt.getAttributeNode("class").value;
  window.alert(attr);
}
</script>
</body>
</html>
